Apparatus for forming filaments

ABSTRACT

The invention pertains to apparatus for producing filaments of varying cross-sectional area and the produced filaments. The apparatus comprises a spinneret having a plurality of plates, at least one of which is vibrated.

United States Patent Hann 51 Mar. 7, 1972 [54] APPARATUS FOR FORMING 2,578,229 1 2/1951 Clement et al, ..18/l2 DM UX FILAMENTS 3,215,094 ll/l965 Oldershaw et al. ..l8/l2 DM UX 3,252,181 5/1966 Hureau ...l8/l2 N 1 lnvemofi Paul Bartlesvllle, Okla 3,274,646 9/1966 Krystof ..l8/l2 DM x [73] Assignee: Phillips Petroleum Company FOREIGN PATENTS OR APPUCATONS m] 1970 486/66 l/l966 Japan ..l8/8 SR [211 App]. No.: 49,739

Primary Examiner-4. Spencer Overholser Related Apphcauon Dam Assistant Examiner-Michael 0. Sutton [62] Division of Ser. No. 560,714, June 27, 1966, Pat. No. Attorney-Young and Quigg ABSTRACT [52] US. CL ..425/76, 425/465 7 511 1m. (:1 ..D0ld 3/00, 0016 5/22 The 'T aPPaamS Pmducmg filamems [58] Field oiSearch ..261/22 23 9- 18/8 SM 8 R cmss'secmnal area and Pmduced The i i Dv apparatus comprises a spinneret having a plurality of plates, at

least one of which is vibrated.

A sz a wasawaew w,

UNITED STATES PATENTS 2,487,910 11/1949 Waddell et al ..l8/ 129114 11X PATENTED 9 2 3,647, 330

SHEET 2 BF 2 INVENTOR.

P1 D. HANN A T TOR/VEYS APPARATUS FOR FORMING FILAMENTS This is a division of application Ser. No. 560,714, filed June 27, 1966, now US. Pat. No. 3,538,206.

This invention relates to apparatus for producing filaments. In one aspect, this invention relates to apparatus for producing filaments of particular cross section. In another aspect, this invention relates to apparatus for producing filaments of varying cross-sectional configuration.

In the formation of filaments by extruding a molten material through a spinneret, it is known to impart vibrations to the spinneret for the purpose of establishing sinuous stresses in the individual filaments. It is stated that the sinuous stresses cause the filaments to contract and thus become crimped. While these stresses are apparently effective for this purpose, the cross-sectional configuration of the filaments cannot be controlled and thus remains substantially unchanged throughout the length of the filaments.

According to this invention, filaments having a varying cross-sectional area are produced by extruding a filamentforming material through an extrusion head in the form of a spinneret which includes a first plate having a plurality of orifices and a second plate in register with the first plate and having a plurality of orifices in register with the orifices in the first plate. The orifices in the first and second plates serve as passageways through which the material is extruded to form the filaments. A vibration means connected to one of the plates is actuated to impart movement to the plate to vary the cross-sectional area of the passageways during extrusion of the organic material. This causes the passageway to change in cross-sectional area from circular to marquise or navette in an alternate manner. While it is within the spirit and scope of the invention to impart the vibrations from a single direction only, it is preferred to vibrate one of the plates successively and repeatedly from a first direction for a first period of time, from a second direction offset from said first direction about 45 for a second period of time, from a third direction offset from said first direction about 90 for a third period of time, and from a fourth direction offset from said first direction about 135 for a fourth period of time. This technique for imparting the vibrations to the plate produces filaments having alternate zones of circular and marquise cross section wherein the major axis of the marquise in the several zones of marquise cross section lie in different planes. When the vibrations are imparted to the plate from the directions described above, the major axes of the marquise in the several zones will be offset by about 45 between adjacent zones. If desired, the plate can be vibrated from different directions varying by amounts other than 45 or from different directions at random. This produces filaments wherein the plane of the major axes of the marquise in the zones of marquise cross section are offset by different angular amounts or randomly. It is also within the spirit and scope of the invention to vibrate both plates at the same time from different directions and to vary the direction of vibration of either plate in measured amounts or at random.

The filaments formed in accordance with this invention tend to bend along the major axis of the smallest marquise in the zones of marquise cross section. This phenomena results in a curled filament which has a high degree of crimp or bulk. When the individual filaments from the spinneret are bunched to form a tow and eventually a yarn, the random and highly crimped or curled configuration of the filaments prevents packing and results in a highly bulked yarn.

Accordingly, it is an object of this invention to produce filaments having a varying cross-sectional area. Another object of this invention is to provide a method and apparatus for producing filaments. A further object of this invention is to produce a highly crimped or curled filament. These and other objects of the invention will become apparent to one skilled in the art after studying the following detailed description, the appended claims, and the accompanying drawings wherein:

FIG. 1 illustrates an apparatus partly schematic and partly in cross section according to the invention;

FIG. 2 is a partially broken plan view of a spinneret constructed in accordance with the invention;

FIG. 3 is a cross section of a spinneret of the invention with the passageways aligned to produce a filament having a circular cross section;

FIG. 3a is a cross section of a filament fonned by passing through the spinneret with the passageways in the position illustrated by FIG. 3;

FIG. 4 is a cross section of the spinneret with one plate offset for producing a filament of marquise cross section;

FIG. 4a is a cross section of a filament formed by passing through the spinneret with the passageways in the position shown by FIG. 4;

FIG. 5 is a plan view of one plate of the spinneret with a schematic illustration of a vibration means including a switch means for controlling the vibrationmeans in a predetermined manner; and

FIG. 6 is a schematic illustration of the structural characteristics of a single filament formed in accordance with the invention.

Referring now to the drawings, wherein like reference numerals are used to denote like elements, the invention will be described in more detail. Many motors, valves, controls, switches, etc., not necessary in explaining the invention to one skilled in the art, have been omitted from the drawings for the sake of clarity.

In FIG. 1, a chamber 1 contains a filament-forming material in the form of a melt 2. An extrusion head 3 attached to chamber 1 includes a first plate 4 having a plurality of orifices 6 and a second plate 7 having a plurality of orifices 8. A plurality of filaments 9 formed by extruding the melt through the passageways formed by the orifices 6 and 8 is solidified and passed over directional rolls I1 and 12 to a takeup reel 13. A vibrator 14 is positively connected to plate 7 in a manner which will cause the plate to move in response to the vibrations from the vibrator 14. If desired, the vibrator can be attached to plate 4 and the extrusion head 3 modified slightly to allow plate 4 to be moved relative to plate 7 in response to the vibrator. Any vibrator such as an electrically energized coil or an electrical transducer such as a piezoelectric member or laminated nickel plate can be used in the practice of the invention.

FIGS. 2, 3 and 4 illustrate the two plates 4 and 7 of the extrusion head in more detail. FIG. 3a illustrates a filament 16 of circular cross section which is formed by extruding the melt 2 through the passageways formed by orifices 6 and 8 when they are in the position illustrated by FIG. 3. FIG. 4a illustrates a filament 17 having a marquise or navette cross section which is formed by extruding the melt 2 through the passageways formed by orifices 6 and 8 when they are in the position illustrated by FIG. 4. As plate 7 alternates between the positions illustrated by FIGS. 3 and 4 in response to the vibratory energy applied thereto, the filaments formed by extrusion through the passageways will have alternate zones of circular and marquise cross section.

In FIG. 5, each of a plurality of vibrators l8, 19, 20 and 21 is connected to plate 7 in a manner which will allow the plate 7 to be vibrated from several different directions. A multipoint stepping switch 22 driven as desired by motor 23 will transmit electrical current from a suitable source (not shown) to each of the vibrators as contact arm 24 rotates and engages each of the contact points of the stepping switch. When contact arm 24 is positioned for transmitting electrical current to vibrator 18, plate 7 will vibrate in a vertical plane as viewed in FIG. 5. As the contact arm 24 is rotated clockwise in response to motor 23, the vibration will be imparted to plate 7 successively and repeatedly from a second direction by vibrator 19 which is offset from the vibrations obtained from vibrator 18 by about 45, from a third direction by means of vibrator 20 which is offset from the vibrations of vibrator 18 by about and from a fourth direction by means of vibrator 21 which is offset from the direction of the vibrations from vibrator 18 by about By regulating the speed of rotation of the contact arm 24, the duration of the vibrations from each of the directions can be controlled as desired.

In all cases, the major axis of the marquise which defines the cross section of the filaments is substantially perpendicular to the direction at which the plate is vibrated. Thus, by imparting the vibrations to the plate from the several different directions successively and repeatedly in the manner described, the major axis of the marquise in the zones of marquise cross section will lie in different planes. When the vibrators l8, 19, 20, and 21 are operated at random rather than in a predetermined sequence as described, the planes of the major axes of the several zones of marquise cross section will be at random.

In FIG. 6, a filament produced in accordance with this invention has a cross section with alternate zones of circular cross section 24 separated by zones of marquise cross section 26. The major axes of each of the marquise cross sections 26 are offset with respect to each other by about 45. This structural characteristic of the filament is accomplished by vibratingplate 7 from the different directions of vibrators 18, 19, 20, and 21. When a single vibrator is employed and the plate vibrated in one direction only, the cross-sectional configuration of the filament will alternate between circular and marquise with the major axes of the marquise. occupying the same plane.

The cross section of a synthetic filament produced in accordance with this invention alternates between circular and marquise. In a preferred form of filament structure, obtained by vibrating the plate from different directions at random, the major axis of each of the several marquises lies in randomly different planes. The area of the smallest marquise cross section is preferably at least about one-half or more of the area of the circular cross section.

The area of the zones of circular cross section of a synthetic filament produced in accordance with this invention can be represented by the equation produce the novel filament structure of this invention. Exem-.

plary materials include polyamides, cellulose esters, polyesters, polyalkylenes, polyvinyls, and the like.

In practicing the method of this invention, the filament forming material is extruded in molten form through passageways fonned by a first plate having a plurality of orifices and a second plate in register with the first plate and having a plurality of orifices in register with orifices in the first plate. Vibrations are imparted to the second plate during the extrusion of the filament-forming material to vary the crosssectional area of the passageways formed by the orifices and thus produce filaments having the varying cross-sectional configuration. The filaments are solidified as for example by cool ing to a temperature below their melt temperature just as they leave the orifices in the lower plate so that the filaments will retain the produced variable cross-sectional areas. While the vibrations can be imparted at any suitable frequency, it is preferred that the vibrations be within the range of about 100 to about 15,000 cycles per second. It is likewise preferred to impart the vibrations to the plate from several different directions successively to produce a filament with a high degree of crimp or curl.

While the rate of extrusion and frequency of vibration can be coordinated and controlled to provide a higher number of changes in the cross section between circular and marquise per unit length, it is desirable to coordinate these variables so as to provide an occurrence of change of at least about 10 per inch.

While any suitable denier filament can be formed by the techni ue of this invention, it is preferred to ractice the meth with filaments having a denier within e range of about 2 to about 2,000.

The following example illustrates the invention. It is to be understood that the invention is not to be limited thereby.

EXAMPLE Poly(hexamethylene adipamide) having a relative viscosity of 40 is extruded at 280 C. through the spinneret of the invention having orifices of 0.020 inch diameter spaced 0.2 inch or 10 diameters apart on their centers. The lower orifice plate is moved or vibrated randomly at the rate of 500 times a second to cause the filaments to issue with cross sections varying from circular to marquise. The major axis-of the smallest marquise between two circular cross sections is 0.019 inch. The greatest distance between the centers of aligned orifices of the two plates is about 0.0062 inch during a vibration cycle. The filaments issue at a rate of about 250 yards per minute and are quenched with a relatively cold gas to about 100 C. The final bundle of filaments is recovered in a bulked condition, each filament being curled at the locus of the navette or marquise cross-sectional areas.

Although the invention has been described in considerable detail, it must be understood that such detail is for the purpose of illustration only and that many variations and modifications can be made by one skilled in the art without departing from the spirit and scope of the invention.

That which is claimed is:

1. Apparatus for producing filaments each having a varying cross-sectional area comprising a chamber for storing a filament-forming material; an extrusion head attached to said chamber including a first plate having a plurality of orifices and a second plate, said first plate and said second plate being superimposed in the direction of flow therethrough, said second plate having aplurality of orifices in register with the orifices in the first plate to define the passageways, the orifices of said plates being sized to produce filaments having a denier within the range of about 2 to about 2,000, and means including a plurality of vibrators positioned around the second plate to impart vibrations to the second plate from different directions during extrusion of the filament-forming material to vary the cross-sectional shape of the passageways while maintaining registry of at least a portion of the cross section of said orifices at all times to produce undivided continuous filaments having a varying cross-sectional configuration.

2. Apparatus according to claim 1 wherein the first and second plates of said extrusion head are substantially horizontal, and the second plate is situated beneath the first plate.

3. Apparatus according to claim 1 including switch'means connected to a source of electrical power and each of said vibrators for supplying current to each of said vibrators in succession to impart vibrations to the second plate from different directions.

4. Apparatus according to claim 3 wherein said switch means includes a stepping switch. I

5. Apparatus according to claim 1 wherein said plurality of vibrators operate successively.

6. The apparatus of claim 1 wherein the plurality of vibrators impart vibrations successively and repeatedly from a first direction for a first period of time, from a second direction offset from said first direction about 45 for a second period of time, from a third direction offset from said first direction about for a third period of time, and from a fourth direction offset from said first direction about for a fourth period of time. 

1. Apparatus for producing filaments each having a varying cross-sectional area comprising a chamber for storing a filamentforming material; an extrusion head attached to said chamber including a first plate having a plurality of orifices and a second plate, said first plate and said second plate being superimposed in the direction of flow therethrough, said second plate having a plurality of orifices in register with the orifices in the first plate to define the passageways, the orifices of said plates being sized to produce filaments having a denier within the range of about 2 to about 2,000, and means including a plurality of vibraTors positioned around the second plate to impart vibrations to the second plate from different directions during extrusion of the filament-forming material to vary the cross-sectional shape of the passageways while maintaining registry of at least a portion of the cross section of said orifices at all times to produce undivided continuous filaments having a varying cross-sectional configuration.
 2. Apparatus according to claim 1 wherein the first and second plates of said extrusion head are substantially horizontal, and the second plate is situated beneath the first plate.
 3. Apparatus according to claim 1 including switch means connected to a source of electrical power and each of said vibrators for supplying current to each of said vibrators in succession to impart vibrations to the second plate from different directions.
 4. Apparatus according to claim 3 wherein said switch means includes a stepping switch.
 5. Apparatus according to claim 1 wherein said plurality of vibrators operate successively.
 6. The apparatus of claim 1 wherein the plurality of vibrators impart vibrations successively and repeatedly from a first direction for a first period of time, from a second direction offset from said first direction about 45* for a second period of time, from a third direction offset from said first direction about 90* for a third period of time, and from a fourth direction offset from said first direction about 135* for a fourth period of time. 